/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.gaia.translation.types;



import com.bff.gaia.unified.sdk.coders.Coder;

import com.bff.gaia.api.common.typeutils.TypeComparator;

import com.bff.gaia.core.memory.DataInputView;

import com.bff.gaia.core.memory.DataOutputView;

import com.bff.gaia.core.memory.MemorySegment;



import java.io.IOException;

import java.util.Arrays;



/**

 * Gaia {@link com.bff.gaia.api.common.typeutils.TypeComparator} for Unified values that have been

 * encoded to byte data by a {@link Coder}.

 */

public class EncodedValueComparator extends TypeComparator<byte[]> {



  /** For storing the Reference in encoded form. */

  private transient byte[] encodedReferenceKey;



  private final boolean ascending;



  public EncodedValueComparator(boolean ascending) {

    this.ascending = ascending;

  }



  @Override

  public int hash(byte[] record) {

    return Arrays.hashCode(record);

  }



  @Override

  public void setReference(byte[] toCompare) {

    this.encodedReferenceKey = toCompare;

  }



  @Override

  public boolean equalToReference(byte[] candidate) {

    if (encodedReferenceKey.length != candidate.length) {

      return false;

    }

    int len = candidate.length;

    for (int i = 0; i < len; i++) {

      if (encodedReferenceKey[i] != candidate[i]) {

        return false;

      }

    }

    return true;

  }



  @Override

  public int compareToReference(TypeComparator<byte[]> other) {

    // VERY IMPORTANT: compareToReference does not behave like Comparable.compare

    // the meaning of the return value is inverted.



    EncodedValueComparator otherEncodedValueComparator = (EncodedValueComparator) other;



    int len =

        Math.min(

            encodedReferenceKey.length, otherEncodedValueComparator.encodedReferenceKey.length);



    for (int i = 0; i < len; i++) {

      byte b1 = encodedReferenceKey[i];

      byte b2 = otherEncodedValueComparator.encodedReferenceKey[i];

      int result = (b1 < b2 ? -1 : (b1 == b2 ? 0 : 1));

      if (result != 0) {

        return ascending ? -result : result;

      }

    }

    int result =

        encodedReferenceKey.length - otherEncodedValueComparator.encodedReferenceKey.length;

    return ascending ? -result : result;

  }



  @Override

  public int compare(byte[] first, byte[] second) {

    int len = Math.min(first.length, second.length);

    for (int i = 0; i < len; i++) {

      byte b1 = first[i];

      byte b2 = second[i];

      int result = (b1 < b2 ? -1 : (b1 == b2 ? 0 : 1));

      if (result != 0) {

        return ascending ? result : -result;

      }

    }

    int result = first.length - second.length;

    return ascending ? result : -result;

  }



  @Override

  public int compareSerialized(DataInputView firstSource, DataInputView secondSource)

      throws IOException {

    int lengthFirst = firstSource.readInt();

    int lengthSecond = secondSource.readInt();



    int len = Math.min(lengthFirst, lengthSecond);

    for (int i = 0; i < len; i++) {

      byte b1 = firstSource.readByte();

      byte b2 = secondSource.readByte();

      int result = (b1 < b2 ? -1 : (b1 == b2 ? 0 : 1));

      if (result != 0) {

        return ascending ? result : -result;

      }

    }



    int result = lengthFirst - lengthSecond;

    return ascending ? result : -result;

  }



  @Override

  public boolean supportsNormalizedKey() {

    // disabled because this seems to not work with some coders,

    // such as the AvroCoder

    return false;

  }



  @Override

  public boolean supportsSerializationWithKeyNormalization() {

    return false;

  }



  @Override

  public int getNormalizeKeyLen() {

    return Integer.MAX_VALUE;

  }



  @Override

  public boolean isNormalizedKeyPrefixOnly(int keyBytes) {

    return true;

  }



  @Override

  public void putNormalizedKey(byte[] record, MemorySegment target, int offset, int numBytes) {

    final int limit = offset + numBytes;



    target.put(offset, record, 0, Math.min(numBytes, record.length));



    offset += record.length;



    while (offset < limit) {

      target.put(offset++, (byte) 0);

    }

  }



  @Override

  public void writeWithKeyNormalization(byte[] record, DataOutputView target) throws IOException {

    throw new UnsupportedOperationException();

  }



  @Override

  public byte[] readWithKeyDenormalization(byte[] reuse, DataInputView source) throws IOException {

    throw new UnsupportedOperationException();

  }



  @Override

  public boolean invertNormalizedKey() {

    return !ascending;

  }



  @Override

  public TypeComparator<byte[]> duplicate() {

    return new EncodedValueComparator(ascending);

  }



  @Override

  public int extractKeys(Object record, Object[] target, int index) {

    target[index] = record;

    return 1;

  }



  @Override

  public TypeComparator[] getFlatComparators() {

    return new TypeComparator[] {this.duplicate()};

  }

}